Portable electronic devices, such as smart phones and personal digital assistants (PDAs), wearable computers, intelligent clothing and smart artefacts are becoming a part of our everyday environment. Protecting them is becoming more and more important, not only because of the value of the devices themselves, but also because there are means of storing valuable and discrete data and their capability for communication, remote transactions, including m-commerce (mobile commerce) and m-banking (mobile banking).
The authentication of a user of an electronic device may be carried out by using a password, such as a PIN code (Personal Identification Number) which may be difficult to remember. Alternatively or additionally, some devices contain fingerprint-based user authentication systems.
Yet, the protection of these devices is usually poor, especially in “on” state, when not even the PIN code nor the fingerprint authentication protects the information and the device. Clearly, a need exists for an unobtrusive, implicit security mechanism.